Herbicidal compositions



United States PatentG No Drawing. Application April3, 1953, Serial No. 346,781

8 Claims. (Cl. 712.3)

The present invention provides new and valuable compositions possessing selective herbicidal efiicacy' and methods of destroying or preventing plant growth in which such compositions are used.

I have found that improved, very efficient, selective herbicidal compositions are obtained when there areprepared oil-in-water emulsions of chlorine-substituted 3- acetylbiphenyl. As examples of compounds useful for the present purpose may be mentioned the chain-substituted compounds, e. g., 3-mono-, dior trichloroacetylbiphenyl; the nuclearly-substituted compounds such'as 4-chloro-3-acetylbiphenyl, 4,4'-dichloro-3-acetylbiphenyl and the ar-tri-, tetra-, or octa-chloro-3-acetylbiphenyls and compounds containing both aliphatic and aromatic chlorine substitutions such as 5-chloro-3-chloroacetylbi phenyl, ar-dichloro-3-dichloroacetylbiphenyl, etc.

The presently useful chlorine-substituted 3-acetylbiphenyls may be readily prepared by contacting 3-acetyl-' biphenyl with chlorine in the presence or absence of a catalyst and in the presence'or absence oflight. Chlorination of the 3-acetylbiphenyl with substitutionin the aliphatic portion of the molecule takes. place readily by simply passing elemental chlorineinto a solution offthe 3-acetylbiphenyl in the absence of a catalyst but in the presence of sunlight or other'sourceof radiant energy.

Chlorination of the 3-acetylbiphenyl with substitution in the aromatic nucleus of the molecule is effected bycorrducting the reaction in the dark and in'the' presence. of a catalyst known to favor aromatic substitution; e. g.;'.a

heavy metal such'as iron, manganese or lead, or a halide thereof such as ferric chloride, zinc bromide, aluminum chloride, etc. Depending upon the nature of the" catalyst and the, quantity of chlorine used, the catalytic chlorination of'3-acetylbiphenyl may result not onlyin nuclear" substitution, but also in some aliphatic substitution. This' is particularly true in the preparationof the polychlorosubstituted m-acetylbiphenyls The chlorination reaction, whether efiected in the light or in the dark "andeither in the'presence or absence of catalysts is somewhat exothermic. However, no cooling precautions need be employed in the process; and. particu g larly when the polychloro-substituted m-acetylbiphenyls are the desired products, it may even be advantageous to employ moderate external heating. As may be apparent to those skilled in the art, the size of the reactor and reactant quantities may also determine the extent of heating or cooling.

The selective herbicidal efiiciency of the present compounds appears to be directly related to the chlorine content thereof as well as to the presence of the acetyl radical in the meta-position. Thus, the unchlorinated 2-acetylbiphenyl has no injurious effect on plants when 1.0 percent oil-in-water emulsions of the same are applied to the plants, whereas the same quantity of 3-acetylbiphenyl applied to plants in the same manner kills both broadleafed and narrow-leafed plants and dries the leaves thereof. Introduction of chlorine into the 3-acetylbiphenyl, either into the aliphatic and/or aromatic portion During, this time the temperature rose from 2 8 C. fto 3 21" limited, by the following examples:

2,773,758 Patented Dec, 11,

2 of the. molecule, .lessens' toxicityjtowards bro'atleleafed plants without a like decrease in toxicity towardsnarrowleafed plants. Hence the present chlorine-substituted m-acetylbiphenyls maybe employed -very,advan tageouslya for'ridding truck .crop fields, -e. g., beans; strawberrieal' etc. of invading grasses. I As may be apparent to those skilledin'the art, the product obtained by passing: chlorine into m-acetylbiphenyl may contain. some. of the --unchlorinated ketone depending uponthe quautity'ofhalogen used, the reactiong,

conditions employed, and the isolating methods .used.

The presence of a smallfquantit'y ofm-acetylbiphenyl; in 5 the present he'ribicidal compositionshas no. adverse effect. on theefiiciency thereof providedthat the chlorine-co tent of the chlorinated 3-acetylbiphenylis at least .10 per; cent by weight of the active ingredient. A monochlorosubstituted m-acetylbiphenyl has content of 15.4 percent.

Herbicidal compositions containing the present chloro substituted m-acetylbiphenylsfare readily obtained by first preparing a solution thereof in an organic solvent and then adding the resulting solution towater containing an emulsifying agent, to formxan emulsion. Because of the high herbicidal efficiency. of the present compounds, they are present in the-.heribicidal'composition in only very a calculated chlorinesmall concentrations, for'example in concentrations. 011;;

emulsions may be employedto-prevent; plant growth by application to media which normally support plant growth. The present invention is further illustrated, but not Example 1 C. within the first'lO minutes, and thenreturned'to28 The solvent was then shipped off by heating the reaction mixture under partial pressure. The residue was a thic syrupy material; analyzing 14.42 percentchlorine"'(cal-.

culated for "a mono chl oro subs tituted acetylbiphenylj] C14H11OC1, 15.5 percent). Because the chlorination wasexecuted under conditions conducive to chain-chlorination, the product is probably 3-chloroacetylbiphenyl. In the evaluation data of Example 3, it is so designated.

Example 2 This example describes catalytic chlorination of m-acetylbiphenyl in the dark.

A black flask was charged with g. of 3-acetylbiphenyl, 300 g. of sym.-tetrachloroethane, and 5 g. of ferric chloride. with stirring, for a total of about 5 hours. The temperature rose from 25 C. to a high of 42 C. during the reaction. At the end of the chlorination period it had decreased to 25 C. The solvent was then removed from the reaction mixture by distilling in a column under Chlorine was passed into this charge,

' benzenesulfonate.

nightin a vacuum oven with an air stream at25" C. The dried, black oily product (85 g.) thus obtained analyged 44.9g4.percent Cl v(calcd. Cl for-C14MaOC14, 42.5 percent). substituted rn-a'cetylbiphenyl, or a mixture of chlorinesubstitutedm-acetylbiphenyls having an'averageof four chlorinje'substituentsr Probably only nuclear substitution is present. This product is designated as tetrachlorosubstituted S-acetylbiphenyl Example 3'.

. 'Example 3 S r y t t of. he

pounds was conducted as follows:

Respective cyclohexanone solutions of the test compounds shown below were added to water, the quantity of Y solution" employed .being calculated to give emulsions 'contaming 1.0 pe'rcentiand 0.3 percent, respectively, of

the compound to be tested, based on the weight of the total emulsion. The quantity of emulsifying agent used was 0.2 percent by weight, based on the weight of the total emulsion. 'Said emulsifying agent comprised a mixtureoffa polyalkyleneglycol' derivative and an alkyl- "Three week old corn and bean plants were sprayed withthe respective emulsions, two plants of each variety being employed. The spraying was continued until droplets formed on and/or fell'from the foliage and stems of the sprayed plants, up'to-lS. ml. of the emulsion being applied to each plant." The sprayed plants as well as two that time the sprayed plants were compared with the untreated plants in order to determine the extent of injury,-if any. The following observations were made:

' Extent of Injury on- Product Tested, at Percent Concentration Bean Corn I 3-Ch1oroaeetylbiphenyl (Ex. 1):

Tetra-ehloro-substituted acetylbiphenyl (Ex.

A l 4, 4a o.s%-. 3,40 4-Chloroacetylbip 1.0 l 2 0.3% 0 1 2-Acetylbiphenyl: I 7 1.0% -l. 0 o 0 0 3-Acetylblphenyl:

1 0=no' injury; 1-'s1i g t injury; 2=moderate injury; 3=serious injury; 4=plant dead; 4a=1eaves dried.

h 1 lggpared by Friedel-Crafts reaction from biphenyl and chloroacetyl c o e. e

- while the present chlorine-substituted m-acetylbi-- phenylsare most advantageously employed as herbicides It "was thus either a sub'stantially tetra-chloro I chloro-substituted,3-acetylbiphenyls of Examples'land 2 as. well as of some related com by incorporating them into an aqueous emulsion as herein described, they may also be employed in other plantdestroying methods. Thus, they may be incorporated .into solid carriers such as clay, talc, pumice and bentonite to give herbicidal compositions which may be applied to living plants or to surfaces which are to be freed from plant growth. The present chloro-substituted' ketones may also be mixed with liquid or solid agricultural pesticides, e. g., insecticides and fungicides. While solutions of the present .chloro-substituted m-acetylbiphenyls in organic solvents may be employed for preventing and destroying plant growth, I have found that the emulsions possess an improved tendency to adhere to the treated surfaces and that lessof the active ingredient is required to give comparable herbicidal efiiciency.

What I claim is:

1. A herbicidal composition comprising an oil-in-water emulsion of a phytotoxic quantity of a chloro-substituted 3-acetylbiphenyl.

2. A herbicidal composition comprising an oil-in-water emulsion of a phytotoxic quantity of. 3-chloroacetylbiphenyl. i

3. A heribicidal composition comprising an oil-in-water emulsion of a phytotoxic quantity of a chlorination product prepared by passing chlorine into 3-acetylbiphenyl in the dark and in the presence of a metal halide catalyst until approximately 4 moles of chlorine per mole of the 3-.acetylbiphenyl have reacted with said acetylbiphenyl.

4. The method of destroying undesired plants which comprisesapplying to said plants a toxic quantity of a herbicidal composition containing as the essential active ingredient a chloro-substituted 3,-acetylbiphenyl.

5. The method of destroying undesired plants which comprises applying to said plants a toxic quantity of a herbicidal composition containing 3-chloroacetylbiphenyl as the essential active ingredient. Y

6. The method of destroying undesired plants which comprises applying to said plantsa toxic quantity of a herbicidal composition containing as the essential active ingredient a chlorination product prepared by passing chlorine into 3-acetylbiphenyl in the darkand in the pres? ence of a metal halide catalyst until approximately 4.

' moles of'chlorine per mole of the 3-acetylbiphenyl have reacted with said acetylbiphenyl.

7. The method of destroying undesired plants which References Cited in thefile of this patent UNITED STATES PATENTS 2,496,067 'Rosenthal Ian. 31, 1950 2,516,098 Bambas July 25; 1950 

1. A HERBICIDAL COMPOSITION COMPRISING AN OIL-IN-WATER EMULSION OF A PHYTOTOXIC QUANTITY OF A CHLORO-SUBSTITUTED 3-ACETYLBIPHENYL. 